According to the SBL Handbook of Style, the abbreviations for books of the Bible, deuterocanonical books, and the Dead Sea Scrolls are not marked with periods. For biblical references, colons normally separate chapters from verses. Semicolons separate chapters, and commas separate verses (SBLHS 8.3.1). For example: Rom 6:3–6, 11–13; 10:9–10, 17.

Old Testament (Hebrew Bible)

Gen – Genesis
Exod – Exodus
Lev – Leviticus
Num – Numbers
Deut – Deuteronomy

Josh – Joshua
Judg – Judges
Ruth – Ruth
1–2 Sam – 1–2 Samuel
1–2 Kgs – 1–2 Kings
1–2 Chr – 1–2 Chronicles
Ezra – Ezra
Neh – Nehemiah
Esth – Esther

Job – Job 
Ps/Pss – Psalm
Prov – Proverb
Eccl – Ecclesiastes
Song – Song of Solomon
(or Cant)

Isa – Isaiah
Jer – Jeremiah
Lam – Lamentations
Ezek – Ezekiel
Dan – Daniel

Hos – Hosea
Joel – Joel
Amos – Amos
Obad – Obadiah
Jonah – Jonah 
Mic – Micah
Nah – Nahum
Hab – Habakkuk
Zeph – Zephaniah
Hag – Haggai
Zech – Zechariah
Mal – Malachi

New Testament (Christian)

Matt – Matthew
Mark – Mark
Luke – Luke
John – John

Acts – Acts

Rom – Romans
1–2 Cor – 1–2 Corinthians
Gal – Galatians
Eph – Ephesians
Phil – Philippians
Col – Colossians
1–2 Thess – 1–2 Thessalonians
1–2 Tim – 1–2 Timothy
Titus – Titus
Phlm – Philemon
Heb – Hebrews

Jas – James
1–2 Pet – 1–2 Peter
1–2–3 John – 1–2–3 John
Jude – Jude

Rev – Revelation